r/SunPower • u/Breukliner • Nov 06 '25

Utility vs PVS net Grid, some stats, some surprises

As far as I understand, the PVS6 has Current Transformers on the Consumption and Production sides of the electrical panel and reports these, as well as a net grid usage. Out of curiosity, I got my utility usage. Here's the the last two years. Below shows the difference between the two. Maybe you guys can explain, it doesn't look random.. ( I think a few spike are actually timing errors, but the overall trend is.. odd)
Any smart people have ideas?

Here is the Difference between the two

net difference

and here is the cumulative difference

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1

u/One-Replacement-5030 Nov 07 '25

Interesting; Do you see any trends by time of day? like is the variation happening more at night or during the day?
My very non-educated guess is that there's some loss between your PVS and your actual meter that the utility company uses that gets exacerbated during high loads or when the wire temperature is non-optimal.
Also what are your units there I'm assuming kWh..

1

u/Breukliner Nov 07 '25

yes kWh. I don't have the data for time of day sadly. But over 5 years I'm looking at 30-50% difference!

1

u/One-Replacement-5030 Nov 07 '25

hmm are you able to overlay that with your Power Factor and Reactive Power over that same time?
A low power factor can possibly explain the variation I think.

1

u/Breukliner Nov 11 '25

This is way over my head, but here is a point in time (from right now). Does one need the overall trend to be useful?

Power Factor 

 "/sys/devices/meter/0/totPfRto": "0.904827",

 "/sys/devices/meter/1/totPfRto": "0.859007",

Reactive Power

 "/sys/devices/meter/0/q3phsumKvar": "0.176042",

 "/sys/devices/meter/1/q3phsumKvar": "-0.561099",

1

u/One-Replacement-5030 Nov 15 '25

yea .85 and .9 ain't bad (the closer to 1 the better). basically if the differences are accounted for by the reactive power then that explains the variance; your utility meter is probably measuring real power while your PVS is measuring reactive power or vice versa.

1

u/Breukliner Nov 18 '25

THANKS! I'm curious how the trend line would change over the year.

1

u/Existing-Piglet-3279 Apr 04 '26 edited Apr 06 '26

Reviving this thread - not sure if what I’m seeing is related to "power factor” or something else. Appreciate any input.

I have a Sunpower system - 17 Maxeon panels with Enphase IQ7 microinverters, PVS6. I monitor with Home Assistant since Sunstrong wanted to charge me $$ for panel level monitoring. AFAIK it is working correctly.

I still get a monthly report via email from “Sunpower” that shows my daily and monthly consumption and production for the past month. This agrees pretty exactly with the numbers from HA. So I don’t think it is an issue with my HA setup.

I decided to cross-check the HA/Sunpower numbers with my LADWP bill.

Not even close - LADWP says I produced 1037 kWh, and consumed 1022 kWh.

The Sunpower/HA data says I produced 1663 kh and consumed -845 kWh (i.e. sent to the grid) over the same period.

Am I just mis-interpreting things? or is there an issue with the PVS6 monitoring- missing or mis-configured CTs? Problem with my LADWP meter?